Microsoft will be launching its Windows Phone 7.8 upgrade on Wednesday, if rumors reported by Tonis Tech Blog today are correct.

The blog cited unnamed sources "near the subject." Meanwhile, WPCentral found some Finnish promotional materials that revealed there will be another update after the 7.8 update.

The materials also appear to shed some light on new features. The operating system will have a new start screen and more color themes to chose from, according to the translation posted to WPCentral.

CNET has contacted Microsoft for a comment and will update when we hear back, but a Microsoft spokesman told TechCrunch that the company will share more details surrounding WP 7.8 "in the near future."